Technical Field
The following description relates to aspects of a sheet feeder, and a method and a computer-readable medium therefor.
Related Art
Heretofore, a sheet feeder has been known that is configured to detect multi-feed in which multiple sheets are simultaneously fed in a mutually-overlapping manner, using an ultrasonic sensor. For instance, the known sheet feeder may detect the multi-feed by detecting a thickness of a sheet using the ultrasonic sensor and comparing a detected thickness value from the ultrasonic sensor with reference values. The reference values may include a reference value for detecting multi-feed and a reference value for detecting the sheet thickness.